1. Field of the Invention
The present invention relates to a burn-in equipment for screening out a defective semiconductor and, more particularly, to a burn-in equipment capable of conducting burn-in at an optimally set burn-in temperature.
2. Description of the Related Art
Conventionally, dynamic burn-in screen test is carried out when, for example, semiconductor devices are received, by burning in the semiconductor devices in a burn-in chamber while inputting burn-in signals to the semiconductor devices from a signal generator.
A burn-in equipment comprises, for example, a burn-in chamber, a characteristic monitoring unit made up of an IC tester, etc., a temperature controller for controlling the temperature inside the burn-in chamber, a burn-in control unit for controlling start and stop of burn-in and a timer unit for setting a burn-in time.
A semiconductor device to be tested, such as an LSI, is mounted on an IC socket provided to a burn-in card and accommodated in the burn-in chamber.
In the burn-in chamber, a temperature sensor for measuring the temperature inside the chamber is provided. The temperature inside the burn-in chamber is detected by the temperature sensor, the temperature inside the burn-in chamber is kept at a predetermined temperature by the temperature controller, a burn-in signal is inputted, and a burn-in acceleration test of a semiconductor device is conducted.
Conventionally, the temperature inside a burn-in chamber is set in advance to the value which is calculated by an operator based on the thermal resistance value, etc., of the specifications of the IC so that the temperature inside an IC chip will be brought to a desired temperature.
However, in a conventional burn-in equipment, the power source current may fluctuate because of the variations in the quality of production lots the semiconductor devices, therefore, the burn-in acceleration test was not always conducted at an expected temperature inside a chip.
Further, the burn-in acceleration test was not necessarily conducted with a proper burn-in time.
Furthermore, in a conventional burn-in equipment, it was impossible to analyze in detail, e.g. which portion of an IC was defective, when a defect was found.